1. Technical Field of the Invention
The present invention relates to communication monitoring apparatuses. More particularly, it relates to communication monitoring apparatuses which monitors the transfer of data communications performed among computers which are connected over a network.
2. Description of the Related Art
Because communication monitoring apparatuses prevent trouble over networks beforehand and are aware of how the networks are being used, they are used on different types of networks to understand locations which may produce trouble over networks. For example, a communication monitoring apparatus on a local area network (hereinafter, referred to as LAN) commonly use a management standard called SNMP (Simple Network Management Protocol). Relevant facts of standards which are conventionally used for communication monitoring apparatuses will be explained below.
FIG. 4 is a diagram which illustrates a simplified structure of a typical communication monitoring apparatus within a LAN. In FIG. 4, 10 is a network such as a LAN. A plurality of computers 20 and analyzing apparatuses 30 are connected to this network 10. In FIG. 4, only one computer 20 and only one analyzing apparatus 30 is illustrated and any others have been omitted from this diagram. Also, in addition to the computer 20 and the analyzing apparatus 30, relaying apparatuses such as routers and repeaters are connected to this network 10.
The above mentioned computer 20 may be, for example, a general personal computer. It may be equipped with a card to connect to a LAN such as an ethernet card, and is connected to the network 10. Also, the analyzing apparatus 30 monitors the status of the communication at location where the computer 20 is connected, and is a console having a processing means for a network administrator. This processing means may be, for example, a software for collecting data on the amount of communication in units of time at the location where the computer 20 is connected.
A communication protocol for allowing communication via the network 10 is installed in the above mentioned computer 20 and the analyzing apparatus 30. Hereinafter, the expression "the computer is connected to the network" signifies that the computer is able to perform data communication with other computers connected to the network.
The above mentioned network 10 may be formed, for example, by a bus-type network standard such as the ethernet, and may use CSMA/CD (Carrier Sense Multiple Access with Collision Detection) as the transmission right controller, and may use TCP/IP (Transmission Control Protocol/Internet Protocol) and such as the communication protocol.
Moreover, the computer 20 and the analyzing apparatus 30 possess a protocol for communicating network management information usually called SNMP protocol group. According to the standard, RMON (Remote Network Monitoring), which is chosen here as an example of the processing procedure relating to network monitoring, the computer 20 takes a data packet transferred over a LAN, executes an analyzing process, and creates and updates a management information table which is set beforehand such as MIB (Management Information Base).
In order for the analyzing apparatus 30 to obtain this management information table, the analyzing apparatus 30 transmits a set command to the computer 20. In accordance with the received command, the computer 20 extracts desired information from the management information table and transmits the management information to the analyzing apparatus 30. The analyzing apparatus 30 collects the management information from a plurality of locations, not illustrated in the diagram, in a similar manner. It then executes an analyzing process of the status of communications, and performs a process of displaying the information to the network administrator.
The above mentioned conventional communication monitoring apparatuses have the objective of management of networks of simple structure such as LAN's. Although these communication monitoring apparatuses are appropriate for use on a simple-structured network, they are not appropriate for networks including small scale terminals ard apparatuses or networks which perform communication by selecting different communication methods, as explained below.
Here, the above mentioned small scale terminals and apparatuses may be, for example, terminals which have limitations such as battery, weight or size restrictions as in portable terminals. Also, the above mentioned networks which perform communication by selecting different communication methods may be, for example, networks which allows the selection of an appropriate communication protocol from among a plurality of communication protocols in cases where a plurality of communication protocols are mixed within a network or where an appropriate network is selected from a plurality of networks of different types which are all connected to a network for the objective of realizing a working communication.
In the conventional method, the protocol for performing the transfer of network management information which is installed in the computer 20 and the analyzing apparatus 30 is too large to install in small scale terminals and apparatuses such as portable terminals. As a result, the burden carried by the computer 20 and the analyzing apparatus 30 is great. Moreover, the selection range of the communication protocols of the network 10 has increased and has correspondingly become complicated. Then, the management information tables become complicated even for conventional LAN's. Yet, the commands become further complicated. And in the end, the scale of the protocol software installation become even more larger.
The installing of the above mentioned analyzing process which the computer 20 is performing according to the conventional method in the small scale terminals and apparatuses such as the portable terminals also increases the burden of the computer 20.
Additionally, in the conventional method, when a specified computer selects an appropriate communication protocol from among a plurality of communication protocols and realizes the desired communication, information relating to the communication quality is transferred from the computer 20 to the analyzing apparatus 30. Consequently, because the specified computer aides in the selection of a communication protocol, it is not possible for the specified computer to use the information from the analysis result.
Further, when a plurality of networks of different types are connected and an appropriate network is selected from among the networks to realize communication, that is, in a, communication environment where different types of networks coexist, in order to perform communication monitoring in each of the networks, it is necessary to install a monitoring means identical to the communication protocol of the analyzing process and network management information installed in the computer 20 into the computers of each of the networks according to the conventional method.
Therefore, although analysis is performed for each of the networks, there is a problem of not being able to easily obtain a comprehensive information of the entire network in the case where specified small scale terminals do not have installed any means for analyzing which network is appropriate for performing their desired communication.
Additionally, in the case where a certain terminal is connected to a public network, for example, the terminal uses a public telephone line to connect to a specified LAN, the network monitoring means which is connected to that LAN is unable to obtain information relating to the status of communications of the public network and is unable to easily express the information relating to the appropriateness of the public network selection to the terminal and the terminal user.